Dry-kiln for drying lumber and other moisture-bearing substances.



H. D.-TIEMAN N.- DRY KI'LN FOR DRYING LUMBER AND OTHER MOSTURE BEARING SUBSTANCES.

APPLICATION FILED DEC-18,1915- Patented June 5, 1917.

LIE. 28,989

N|| 00560066 GOGQAQQ euuaowoeoeaoeaao QFFICE. 1

,- v i .IIEMANN, or ivm nison, WISCONSIN.

Y niziz-Kmn its :la aiir151e1"iti'nirmiza AND OTHER MOISTURE-BEARING snBsrANcEs.

Toall whom it v Be it known that I,"HARRY,D TIE.

MANN, a citizen ofthe Uniteds fi 'claimed may be used by the Government of employee of the Departmentiof Agriculture of the said United States -of'America,iresiding at Madison, in the county of Dane, State of Wisconsin, (whose post-oflice address is Madison,Wisconsin,) have invented certain new and; useful llmprowements in. ,jDry-Kilns' forajDrgingfi. Lumber and other u Moisture-Bearing bstances." v This application is made ,under the act of the UnitedState sor any of'its' officers or employees-in theyproseeution of. work for the Government, or any person in the United States, without payment to me of an'yroyalt thereon.

1 y invention is an improvement on my former dry ki described in Letters Patent and improvement consists primarily an ar- ,ran'gement of parts by'which advantage is i -taken. of the natural tendency of cooled air to descend as it is cooled by the pile of'lumxfber being dried, and at the same time the. features of. humidity.'reg ulation and increased circulation by means of sprays of T" water, claimed in my former patents, here 'inbefor'e referred to,--are' retained in the im- -,;pmvea .dr kiln herein described. 3 5

'- The: object of my invention isv to increase the circulation ofthexair', within the pileof lumber and at thesame time to regulate the humidity-r r. the .air'; passing through the pile,-'so as to1 obtain more rapid, uniform and. thorough: drying than has been accomf plish'edj heretofore,

"'i thatyaljy substance 'fromzwhich moisture is 5o cooler-within apilefojf lumberand also that ".it tends to descend. Experiments on a com- .-:-meria1 scale have'shown that this tendency is f. considera le co seq en e a d Itf..is well thatiin any given in- "closure the,cooler air tends 'to descend by jreasonfof' its greater density, f and the w'aa mer air to rise. It isalso well known a Specification of Illetters I' atent. I Patented June 5,1917, a ncat i ani aneu b r 18,1 15, serial at. 67,615.

' nn iiIca'rEnro THE rustic.) I

-"cially so'when the lumber is frozen when.

first placedin the kiln.

. The nature and scope of my invention will be more readily understood by'the following'description taken in connection with the accompanying drawings, wherein I have illustrated a cross sectlon of my improved kiln with a load of lumber in the form of, boards in place. The kiln may be either of the pr ressive or the compartment form. a

In the ormer a chamber much longer than Figures 1 and 2 show cross-sections of two formsof drying ln'lns.

. Referring to, the drawingsz li represents the lumber placed in-piles, and B a vertical flue about 8 or 12 inches wide running the; entire length of the kiln through the center truck loads of lumber are placed in the kiln i and remain stationary until they are dry.

or one flue on either side and formed by the waterproof partitions, C. D indlcates suitable. b'afiie plates consisting of a series of;

boards placed in zigza fashion as shown at fine mist from the air and allow this airto pass through in a saturatedcondition but free from'entrained particles of water.

represents a spray of water running the length ,of the flue, which is supplied from 11, the purpose of w ich is to separate the p suitable nozzles, Gr, the temperature of the 'water being regulated by means of'a tem-;

perature regul'ator, G. Arranged at the 7 bottom of the kilnis a gutter, H, for collecting the drip and-returning it to any desired I place. The temperature -of the spray of water, F, may bealtered at will, a suitable apparatus for efiecting such change in temperature having been described in my for, mer patents, referred to above. I also provide a seriesjofcold-water condenser pipes, I, for use at'the end of the drying operation when very lowhumidity isrequired. Steam heating pipes, J, are so placed that the chief heating: efl'ect is produced where the upward current-of air is desired. Auxiliary heating pipes, L, may be placed near the top of the column of upward rising air to maintain its temperature constant, when ever cooling occurs through contact withthg side walls butare not essential to the ap-' paratus. Solid baflie plates, M, are arranged below the piles of lumber, A, to direct the flow of heated air and to shield the lumber from the radiation of the steam pipes, J. N is a perforated steam pipe, for use, if needed, for extremely high humidities and high temperatures.

It will be noted that the lumber as shown is piled in an inclined manner, the downward slope being in the same direction as the descending air currents. This slope is not an essential part of my invention but facilitates the natural tendency of the air to descend as it cools. My invention applies tering the kiln the inner rails drop below opposite side of the pile.

the level of the outer rails, thus automati- .cally inclining the lumber in the desired fashion. The lumber may be piled on a sloping truck with the rails horizontal, if preferred.

In practising my invention the load of lumber is run into the kiln, and the door is closed as nearly air tight as possible. The entire kiln is thus shut 01f from the outside air, there being no ventilators or communications with the outer air. ,It is thus independent of atmospheric conditions, which is of great advantage. The air is heated by the pipes, J, and rises along one side .of the pile of lumber, A. As the heated air comes in contact with thecold wet wood portions of'it are cooled and descend between the layers of boards to'the Here the cooled air sinks downward and a part enters the spray-flue, B, where it is cooled or heated as the case may be by intimate contact with the spray of water, F, and is reduced to a. completely saturated condition. A steam spray may be used also in conjunction with the Water spray in the flue, B, whenever' excessively high humidities at hi h temperatures are called for, though or inarily this will not be needed. The air then passes through the eliminators D, into the space beneath the heating pipes, J, still in a saturated condition and at a certain desired temperature. This temperature is the dew-point of the air after it passes through the heaters, J. This dew-point temperature is controlled by the temperature of the water used in the sprays, F. Thus any desired humidity intheair above the heating pipes, J, can be maintained. The sprays furthermore greatly increase the circulation through the downward force of the water in the narrow chamber, B. By the use of hot water the dew-point temperature is raised and consequently the air 1s humidified. When cold water is used the dewpoint is lowered and the air is dried, the sprays acting as condensers.

For very dry conditions I have found here the sprays are particularly efficient.

A small space, as shown at 22, is left on either side of the flue, B, between it and the lumber, to permit of a certain amount of local circulation, whichfadds to the efficiency of the process, without any additional expenditure of heat.

From the foregoing, it is thought that the construction, operation and many advantages of the herein described inventlon will be apparent to those skilled in the art, without further description, and it will be understood that various changes in the size, shape, proportion, and minor details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

Having thus described my invention, I claim:

1. In a dry kiln consisting of a closed chamber, the following sequence of parts: heating pipes arranged so as to produce an ascending column of heated air along one side of the pile of lumber; a pile of lumber so arranged that the heated air may pass freely through the pile in cooling, in a downward direction; said lumber being so ,piled as todeave a space on the opposite side of the pile through which the cooled air may descend; 'a vertical flue near the bottom of the pile, into which the cooled descending column of air may enter; a spray of water in this flue; means for regulating the temperature of this spray of water; baflle plates near the bottom of this flue for separating the mist from the air, substan tially as described.

2. In a dry kiln consisting of a closed chamber the following sequence of parts: heating pipes arranged so as to produce an ascending column of heated air along one side of the pile of lumber, an auxiliary heater placed near the topof the ascendin through the pile in cooling in a more or less downward direction; said lumber being so piled as to leave a space on the opposite side through which the cooled air may descend as it emerges from the lumber; a set of pipe condensers in the descending column of air; a vertical flue near the bottom of the pile into which the cooled descending column of airmay enter; a spray of water in this flue; means for regulating the temperature of this spray of water; baffie plates near thevbottom of this flue for separating the mist from the air, substantially as described.

3. In a dry kiln consisting of a closed chamber, the following sequence of parts: heating pipes arranged so as to produce an ascending column of heated air along one side of the pile of lumber; an auxiliary heater placed near the top of the ascending column of air; a pile of lumber so arranged as to allow the heated air to pass freely through the pile in cooling in a more or less downward direction; said lumber being so piled as to leave a space on the opposite side through which the cooled air may descend as it emerges from the lumber; a set of pipe condensers in the descending column of air; a vertical flue near the bottom of the pile into which the cooled descending column of air may enter; a spray of water in this flue; means for regulating the temperature of this spray of water; a perforated steam pipe in this flue; baflie plates near the bottom of this flue for separating the mist from the air, substantially as described.

In testimony whereof, I aflix my signature in the presence of two subscribing witnesses.

HARRY DONALD TIEMANN.

Witnesses:

HARRY IRIoN, W B. GREELEY. 

